Worksites, such as, for example, mine sites, landfills, quarries, construction sites, etc., commonly undergo geographic alteration by machines and/or workers performing various tasks thereon. For example, at a coal mining site, mounds of coal are continually moved by dozers, excavators, and/or other digging machines about the site. Haul trucks or other similar machines may transport the coal or other mined material for processing. On many sites, digging machines are matched with appropriate hauling machines for maximum productivity and/or efficiency. These hauling machines may travel on several paths from a digging site where they are loaded, to a dumping site where they are unloaded. Some work sites employ autonomous or semi-autonomous machines. These machines may be operated without an operator in the machine, or control systems on the machines may perform some operations without input from an operator.
To allow autonomous, or semi-autonomous machines to traverse paths or roads on a work site, the terrain of the worksite may be digitally mapped in a digital site map. The digital site map may be contained in a memory component in a controller of a machine. The digital site map may be updated by the controller of the machine, a transmission of terrain changes from another machine, and/or an off-board transmission. The machine may be operated autonomously to travel on a path and complete an operation through utilizing the digital site map, the machine's present location, and a selected travel path. The machine controller and/or an off-board system may select travel paths for the machine.
Some machines may have GPS systems which sense the machine's position. However some machines may not be equipped with a GPS system, or GPS receivers may not be able to receive needed signals from satellites because of the terrain of the worksite at some or all times. Some sites have pseudolites or other location identifiers at different positions on the mine sites. However, machines operated autonomously may need to update their locations more frequently than these location identifiers allow.
The disclosed system is directed to overcoming one or more of the problems set forth above.